Rigid hull inflatable boat with foam insert

ABSTRACT

A boat with an inflatable collar mounted on the sides of the hull. The inflatable collar extends outwardly from the sides of the hull so that it contacts and displaces an increasing volume of water as the boat lists. The inflatable collar is partially filled with foam, and the foam inserts are sized so that the boat retains a sufficient righting moment for its intended purpose even when the inflatable collar has lost its water and airtight integrity. The foam inserts may also be sized to provide the boat with sufficient buoyancy to ensure that the boat will float even if filled with water or capsized.

CROSS-REFERENCE TO RELATED APPLICATION

[0001] This application claims the benefit of U.S. ProvisionalApplication Ser. No. 60/261,350, filed Jan. 12, 2001.

FIELD OF THE INVENTION

[0002] The present invention relates to boats that are stabilized withbuoyant stabilizing members. Specifically, the present invention relatesto boats that have rigid hulls and inflatable collar with a foam insertstabilizing member attached to the sides of the hulls and extendingsubstantially around the perimeter of the hull.

BACKGROUND OF THE INVENTION

[0003] It is very important to design smaller boats with flotationdevices in the hull to ensure that the boat remains floating in casesubstantial water gets into the boat or the boat capsizes. Additionally,flotation devices provide the boat with added buoyancy, thus increasingcarrying capacity and safety. The installation of flotation devices isespecially important in the case of small boats which are designed foroperation on rough waters, such as in the case of rescue boats.

[0004] Many prior art boat designs incorporate foam devices within thehull of the boat, as in U.S. Pat. No. 4,060,865 (Woolworth). Typically,the foam flotation members are incorporated directly within the hullstructure itself. These boat designs are generally safer than designswhich do not incorporate flotation devices within the hull.

[0005] Other prior art boat designs use inflatable cylinders to form thesides of the boat, as in the case of Zodiac® boats. The inflatablecylinders provide a high degree of stability to the boat but result in aloss of performance. Generally, prior art inflatable boat designs useinflatable cylinders as the sides of the boat and either a flexiblefloorboard or a rigid floorboard formed of wood or fiberglass. Inoperation, the cylinders serve as the running surface for the boat andremain in contact with the surface of the water; thus, a substantialwetted surface area and a significant amount of drag are created. Thisdesign also results in a very poor ride due to the fact that the boattends to skip or bounce over the top of the waves. In addition, theinflatable cylinders are easily damaged and must constantly be inspectedfor tears, leaks, etc. Another disadvantage to inflatable boats is thattypically the interior of the boat is very small, thus leaving littleroom for carrying equipment or passengers.

[0006] Another prior art design is a boat stabilized through the use ofoutboard foam stabilizing members. Generally, such prior art designs usea rigid, planing hull having a transom and a pair of curved sidesextending forwardly from the transom to form the bow of the watercraft.The sides and bottom of the hull are joined to form a chine. Foamstabilizers for stabilizing the watercraft are mounted on the sides ofthe hull above the chine and extend from the transom along the length ofthe hull to the bow. The stabilizers extend outwardly from the sides ofthe hull so that they contact and displace an increasing volume of wateras the boat lists. A disadvantage of such foam stabilized boats is thatthe foam stabilizers are harder than the prior art inflatable boats withinflatable cylinders at the sides.

SUMMARY OF THE INVENTION

[0007] The present invention provides a safe, stable, high performanceboat while reducing the disadvantages of prior art designs. The presentinvention's use of a rigid, planing boat hull combined with exteriorinflatable collar partially filled with foam results in these advantageswithout the disadvantages of typical inflatable boat designs.Furthermore, the inflatable collar is substantially out of contact withthe surface of the water when the boat is at cruising speed. Thisdecreases the wetted surface area of the boat when compared toinflatable boat designs, thus increasing performance. An auxiliaryplaning strake can also be provided for use as a running surface when asharp turn is performed at high speed.

[0008] The present invention allows the inflatable collar to be mountedto the sides of the boat hull in such a way that water pressure at highspeeds does not force the inflatable collar away from the boat hull,thus preventing damage to the boat hull or inflatable collar.Furthermore, the inflatable collar is mounted to the hull without holesbeing formed in the sides of the boat, thus ensuring that mounting theinflatable collar on the hull does not create a possibility of leaksinto the interior of the boat.

[0009] An embodiment of an inflatable collar with foam insertswatercraft includes a rigid, planing hull having a transom and a pair ofcurved sides extending forwardly from the transom to form the bow of thewatercraft. The sides and the bottom of the are hull joined to form achine. A single continuous inflatable collar with foam inserts forstabilizing the watercraft is mounted on the sides of the hull above thechine and extends continuously from the transom along the length of thehull to the bow and back to the transom along the opposite side of thehull. The inflatable collar extends outwardly from the sides of the hullso that it contacts and displaces an increasing volume of water as theboat lists. This stabilizes the boat by increasing the righting momentof the hull. The watercraft may include a flange that extends outwardlyfrom the sides of the hull. The flange is adapted to extend below theinflatable collar to ensure that water does not flow between theinflatable collar and the sides of the hull.

[0010] The above and other features of the invention, including variousnovel details of construction and accommodation of parts, will now bemore particularly described with reference to the accompanying drawings.It will be understood that the particular device embodying the inventionis shown by way of illustration only, and not as a limitation of theinvention. Principles and features of this invention may be employed invarious and numerous embodiments without departing from the scope of theinvention.

BRIEF DESCRIPTION OF THE DRAWINGS

[0011] The foregoing aspects and many of the attendant advantages ofthis invention will become more readily appreciated as the same becomebetter understood by reference to the following detailed description,when taken in conjunction with the accompanying drawings, wherein:

[0012]FIG. 1 is a first embodiment of a watercraft stabilized by aninflatable collar partially filled with foam inserts;

[0013]FIG. 2 is a cross sectional view of the inflatable collar withfoam insert of FIG. 1;

[0014]FIG. 3 is a cross sectional view of another embodiment of theinflatable collar with foam inserts; and

[0015]FIG. 4 is a cross sectional view of a third embodiment of theinflatable collar with foam inserts.

[0016]FIG. 5 is a cross sectional view of a fourth embodiment of theinflatable collar with foam inserts.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0017] Referring to FIGS. 1 and 2, an embodiment of a watercraft1stabilized by an inflatable collar 20 partially filled with foam inserts21 is disclosed. In the first embodiment disclosed, the watercraft 1includes a rigid hull 2 and single inflatable collar 20 located on bothsides of the hull. The rigid hull 2 may be formed of aluminum,fiberglass, Kevlar®, or any other suitable material that can withstandthe harsh and corrosive environment encountered by boat hulls. In theembodiment shown, the hull 2 is designed to be a high performance boathull. The hull 2 includes a transom 3 which defines the stem of theboat, two sides 6 extending forward from the stem and curving towardeach other to define the bow 8 of the boat hull, and a bottom 9. In theembodiment shown in FIGS. 1 and 2, the sides 6 are joined to the bottom7 of the boat and to the sides 4 of the transom 3 such that hard chines10 are formed at the intersection between the sides 6 and the bottom 9of the boat 1. A hard chine is formed when two discrete surfaces meet atan angle as opposed to a soft chine where the chine is part of agradually curving surface, such as the surface of a number of sailboathulls. In the embodiment shown, auxiliary planing strakes 11 extendsoutwardly and downwardly from the bottom 9 of the hull 2 near chines 10.The outward most edges 12 of the auxiliary planing strakes 11 curvesdownwardly. Auxiliary planing strakes 11 downwardly deflects water ordebris thrown off by the bottom 9 of the hull 2 as the boat 1 movesthrough the water, thereby protecting the inflatable collar 20 fromdamage. In order to increase safety, while gaining unique performanceadvantages, an inflatable collar 20 with foam inserts 21 is mounted tothe sides 6 of the hull 2 above the chines 10. Mounting the inflatablecollar 20 above the chines 10 as opposed to at or below the chinescreates a number of advantages as explained below. The inflatable collar20 extends from a point rearward of the transom 3 forward along one ofthe sides 6 of the hull 2 to the bow 8 of the boat and then extendsrearward along the opposite side of the hull, as is best shown inFIG. 1. The inflatable collar 20 may include rear extensions 22 whichextend rearwardly beyond the transom 3 in order to provide additionallift in head and following seas, thus increasing the stability of theboat 1. Although it could be advantageous to extend the inflatablecollar 20 beyond the transom 3, it will be understood that it is not arequired aspect of the present invention to do so.

[0018] In the embodiment shown in FIG. 2, the inflatable collar 20 issubstantially cylindrical in cross section. Other embodiments of thecollar 20 are shown in FIGS. 3 and 4. The inflatable collar 20 includesa unitary outer cover 23, attachment mechanism 24, and multiple airbladders 25 contained within the outer cover. The attachment mechanism24 for the inflatable collar 20 includes upper 26 and lower 27 extrudedattachment fittings attached to each side 6 of the hull 2. In anembodiment, the extruded attachment fittings 26 and 27 are made ofaluminum, but may be formed of fiberglass, Kevlar®, or any othersuitable material that can withstand the harsh and corrosive environmentencountered by boat hulls. In an embodiment of the invention in whichthe hull 2 and extruded attachment fittings 26 and 27 are aluminum oranother metal, the extruded attachment fittings are attached by welding.Suitable attachment techniques are known to those skilled in the artwith respect to non-metal hulls or extruded attachment fittings. Eachextruded attachment fitting 26 and 27 runs continuously from the transom3 to a point several inches from the stem of the bow 8. In theembodiment shown, the upper extruded attachment fittings 26 on each side6 of the hull 2 are mounted so that their upper surface 28 is flush withthe tops 13 of the sides 6 of the boat, while the lower extrudedattachment fittings 27 are mounted several inches above the chine 10.The extruded attachment fittings 26 and 27 include lipped channels 29 asshown in FIG. 3. The ends of the lipped channels 29 at the transom 3 arepermanently blocked off, while the ends of the lipped channels near thebow are blocked by any suitable removable fitting.

[0019] The outer cover 23 is made of polyurethane or any other flexiblematerial that can withstand the harsh and corrosive environmentencountered by boat hulls. The outer cover 23 of the inflatable collar20 includes flaps 30 of material disposed on the inward side of theinflatable collar. The flaps 30 are wrapped around ultra high molecularpolyethylene rods 31 and the combination of rod and flap material aresized to slide in the end of the extruded attachment fittings 26 and 27but are too large to pull through the open sides of the lipped channels29. The inflatable collar 20 may be placed on the hull 2 by removing theremovable fitting blocking the forward end of the lipped channels 29,sliding the rods 31 and attached flap 30 material down the length of thelipped channels, and closing the forward end of the channel by replacingthe removable fitting.

[0020] Referring to FIG. 4, the inflatable collar 20 and flaps 30 can besized and positioned so that when the collar is inflated, it protrudesabove the gunwales 14, providing a wide and comfortable sittinglocation. The inflatable collar 20 and flaps 30 can also be sized andpositioned so that the collar is in contact with the water when thevessel is not underway, or positioned so that the collar is not incontact with the water when the vessel is not underway.

[0021] Referring to FIGS. 2-3, the inflatable collar 20 is furtherfitted with one or more internal air bladders 25. The internal airbladders 25 are made of any air and water tight flexible material thatcan withstand the harsh and corrosive environment encountered by boathulls, such as polyurethane. Each internal air bladder 25 furtherincludes a resealable air valve 32 which can be used for inflating ordeflating the air bladder. Each internal air bladder 25 is furtherfitted with a foam insert 21 so that the inflatable collar 20 retainssome capacity to displace water in the event that the internal airbladders 25 lose air and water-tight integrity. In the embodiment shownin FIG. 3, the foam insert 21 is held in position within the internalair bladder 25 by a panel 33 of the material used to form the airbladder. The outer cover 23 optionally includes zipper 34, which can beopened to permit the easy removal and/or replacement of the air bladders25. Removal of the air bladders 25 reduces the width of the boat 1,permitting easier over the road transport. As another alternative, airbladders 25 can be drained of air through resealable air valve 32 toalso reduce the width of the boat 1, whether or not the outer cover 23is fitted with zipper 34.

[0022] The reserve buoyancy foam insert 21 can be formed of any suitablebuoyant foam which can withstand the harsh environment encountered by ahigh speed watercraft, including normal docking and moorage bumping. Itis also advantageous that the foam insert 21 be formed from a foam thatdoes not absorb water, has some memory and is low in density. In thepreferred embodiment shown, a closed cell polypropylene or polyethylenefoam having a density of 1.7 pounds per cubic foot is used to form thefoam insert 21. In view of currently available foam, it is believed thatan optimum range of densities is from approximately 1-3 pounds per cubicfoot. Advances in technology, may result in lower density foam that canbe employed in the invention. The foam insert 21 in the currentembodiment is sized to displace one-half to two-thirds of the volume ofwater displaced by an intact internal air bladder 25. However, the foaminsert 21 can be sized to provide any fraction of displacement relativeto an intact internal air bladder 25, but should be sized so that theboat 1 retains a sufficient righting moment for its intended purposeeven when the internal air bladders have lost their water and airtightintegrity. The foam inserts 21 may also be sized to provide the boat 1with sufficient buoyancy to ensure that the boat will float even iffilled with water or capsized.

[0023] Placing the inflatable air collar 20 above the chine 10 of thehull 2 also creates performance advantages. The use of a rigid planinghull 2 in the present invention allows the inflatable collar 20 to belifted substantially out of contact with the surface of the water duringhigh speed operation. This greatly reduces the wetted surface area andtherefore the drag of the boat 1. Furthermore, the foam insert 21 allowsthe boat 1 to retain a high degree of stability in the event the airbladders 25 lose water and airtight integrity. The illustrativeembodiment is also ideally suited for use in locations where the boat 1may come into contact with other objects. In those circumstances, theinflatable collar 20 will deform without damaging the object that hasbeen struck or injuring any persons that have been struck.

[0024] Referring to FIG. 5, another embodiment is shown wherein the hull2 is a catamaran. In the embodiment shown, the inflatable air collar 20is mounted to the outward most side of each hull sponson 15 above thestatic waterline 16. As with he inflatable air collar 20 mounted to themono-hull, the collar can otherwise have any of the embodimentsdescribed above.

[0025] It is understood that the present invention is by no meanslimited to the particular construction herein disclosed and/or shown inthe drawings, but also comprises any modifications or equivalents withinthe scope of the disclosure.

The embodiments of the invention in which an exclusive property orprivilege is claimed are defined as follows:
 1. A foam and airstabilized watercraft for use on a body of water, the watercraftcomprising: (a) a rigid hull with a bow, stem, bottom and two sides; (b)foam and air stabilizers mounted on the exterior of said hull andextending along at least some portion of each of said sides from saidtransom to said bow, said foam and air stabilizers extending outwardfrom said sides, said foam and air stabilizers further comprising one ormore water and air tight bladders partially filled with pliable closedcell foam.
 2. The watercraft of claim 1, further comprising a pliableprotective material covering the exterior surface of the water and airtight bladders.
 3. The watercraft of claim 2, further comprising azipper in the pliable protective material.
 4. The watercraft of claim 1,wherein the foam is a closed cell polypropylene or polyethylene foam. 5.The watercraft of claim 1, wherein the water and air tight bladdersfurther comprise one or more internal fabric panels holding the foam inplace within said water and air tight bladders.
 6. The watercraft ofclaim 1, wherein the water and air tight bladders further include one ormore air valves in the skin of said bladders, permitting the inflationand deflation of said bladders.
 7. The watercraft of claim 2, furthercomprising one or more lipped channels mounted to the sides of the hull,one ore more flaps of the pliable protective material extending from thepliable protective cover, said flaps wrapped around solid rods, saidflaps and rods sized for insertion into and retention by said lippedchannels.
 8. The watercraft of claim 1, wherein the hull is a mono-hull.9. The watercraft of claim 8, further comprising two or more lowerflanges extending outwardly from the sides of the hull below the foamand air stabilizers.
 10. The watercraft of claim 1, wherein the foam andair stabilizers are mounted above the static waterline.
 11. Thewatercraft of claim 1, wherein the hull is a planing hull and the foamand air stabilizers are mounted so said stabilizers are in contact withthe water when said hull is stationary, and out of the water when saidhull is planing.
 12. A foam and air stabilized watercraft for use on abody of water, the watercraft comprising: (a) a multi-hull hull with abow end, stern end, and two outwardmost sides; (b) foam and airstabilizers mounted on said outwardmost sides and extending along atleast some portion of each of said outwardmost sides from said stem endto said bow end, said foam and air stabilizers extending outward fromsaid outwardmost sides, said foam and air stabilizers further comprisingat one or more water and air tight bladders partially filled withpliable closed cell foam.
 13. The watercraft of claim 13, furthercomprising a pliable protective material covering the exterior surfaceof the water and air tight bladders.
 14. The watercraft of claim 14,further comprising a zipper in the pliable protective material.
 15. Thewatercraft of claim 13, wherein the foam is a closed cell polypropyleneor polyethylene foam.
 16. The watercraft of claim 13, wherein the waterand air tight bladders further comprise one or more internal fabricpanels holding the foam in place within said water and air tightbladders.
 17. The watercraft of claim 13, wherein the water and airtight bladders further include one or more air valves in the skin ofsaid bladders, permitting the inflation and deflation of said bladders.18. The watercraft of claim 13, further comprising one or more lippedchannels mounted to the outwardmost sides of the hull, one or more flapsof the pliable protective material extending from the pliable protectivecover, said flaps wrapped around solid rods, said flaps and rods sizedfor insertion into and retention by said lipped channels.
 19. Thewatercraft of claim 13, further comprising two or more lower flangesextending outwardly from the outwardmost sides of the hull below thefoam and air stabilizers.
 20. The watercraft of claim 13, wherein thefoam and air stabilizers are mounted above the static waterline.
 21. Thewatercraft of claim 13, wherein the hull is a planing hull and the foamand air stabilizers are mounted so said stabilizers are in contact withthe water when said hull is stationary, and out of the water when saidhull is planing.
 22. A foam and air stabilized watercraft for use on abody of water, the watercraft comprising: (a) a rigid hull with a bow,stem, bottom, two sides, and lipped channels mounted to said sides ofsaid hull; (b) foam and air stabilizers mounted on the exterior of saidhull and extending along at least some portion of each of said sidesfrom said transom to said bow, said foam and air stabilizers extendingoutward from said sides, said foam and air stabilizers furthercomprising one or more water and air tight bladders partially filledwith closed cell polypropylene or polyethylene foam, one or moreinternal fabric panels holding said foam in place within said water andair tight bladders, a pliable protective material covering the exteriorsurface of said water and air tight bladders, a zipper in said pliableprotective material, one or more air valves in the skin of said air andwater tight bladders, one or more flaps of said pliable protectivematerial extending from said pliable protective material covering theexterior surface of said water and air tight bladders, said flapswrapped around solid rods, said flaps sized for insertion into andretention by said lipped channel; and (c) two or more lower flangesextending outward from each of said two sides below said foam and airstabilizers.